Biodegradation Of Crystal Violet In Wastewater By Burkholderia Vietnamiensis

Wastewater of the textile industry has been one of major environmental hazards in recent years since the dye and its degradation products are carcinogenic, mutagenic, teratogenic.The wastewater release to envrinment and lead to potential environmental damage since it will pose a great threat to animal, plant and human health. Hence, developing new treatment method to process printing and dyeing industry wastewater with low cost and high efficiency has become a key issue in water pollution control and attracted the attention.To address this issue, a crystal violet-degrading bacterium, designed strain C09V was isolated from the activated sludge of the effluent treatment system (Fuhua Printing and Dyeing Mill, Fujian, China). It is a subspecies of Burkholderia Vietnamiensis based on Gram staining, morphology characters, and biochemical tests, as well as the analysis of16S rRNA gene similarities. Batch experiments were performed under various conditions such as pH, initial dye concentration and media components, for example heavy metals, carbon and nitrogen sources. More than96.1%of crystal violet could be degraded in the solution containing30.0mg/L crystal violet tested at the optima within36h:including glucose, KNO3,5%inoculums size, pH at5.0, and the temperature of35℃. An acceleration in the biodegradation of crystal violet was observed when Cd (II) and Mn(II) were present, in contrast the present of Cu(II) and Ni(II) decrease the decolorization rate. The biodegradation kinetics of crystal violet corresponded to the pseudo first-order rate model. UV-Visible and Fourier transform infrared spectroscopy (FTIR) were used to identify degradation metabolites. UV-Vis showed that the absorption peak at588nm was reduced by the reductively degrades the N-bond linkages, as well as the formation of new bands after degrading crystal violet using free cells by FTIR. Finally, the ability of Burkholderia Vietnamiensis C09V to remove crystal violet in wastewater was demonstrated. More than91.1%of crystal violet could be degraded in wastewater which contains40.4mg/L crystal violet within72h.The stain, Burkholderia Vietnamiensis C09V was immobilized on P VA-alginate-kaolin gel beads as a biomaterial used to improve the degradation of crystal violet in aqueous solution. The results shows that98.6%crystal violet(30.0mg/L) was removed from aqueous solution using the immobilized cells on the PVA-alginate-kaolin gel beads, while only94.0%crystal violet was removed by free cell after degradation at the pH5.0and30℃for30h. Kinetics studies shows that the adsorption of crystal violet on the PVA-alginate-kaolin beads was described well by pseudo-second-order kinetic model, while biodegradation of crystal violet on immobilized cells was fitted well by first-order reaction kinetics, indicating that CV was adsorbed onto kaolin and following degraded by the cells on immobilized onto the the PVA-alginate-kaolin beads. Characterization with SEM shows that cells attached well on the surface of PVC-alginate-kaolin beads, leading to improve crystal violet transfer from aqueous solution to immobilized cells.In addition, the beads maintained physiological stability and high mechanical strength after10cycles. And the degradation efficiency remained higher than91.1%at the10th repeated-batch experiments. The high degradation efficiency and stability of the immobilized cells in reuse test suggest that immobilization technique is a potential for real application.